Docking device for optical shape sensing launch fixtures

ABSTRACT

An optical shape sensing (OSS) system includes a launch fixture configured to receive and secure an optical fiber within a flexible OSS enabled instrument, where the launch fixture includes a docking interface; a launch fixture base configured to be connected to a support structure; and a docking device configured to secure the launch fixture onto the launch fixture base. The docking device includes a launch fixture slot passing through the docking device, and the launch fixture slot is configured to receive and secure the docking interface of the launch fixture through both a top side of the docking device and an opposing bottom side of the docking device.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a Continuation application of U.S. Ser. No.16/252,920 filed Jan. 21, 2019, which is a Continuation-In-Partapplication of U.S. Ser. No. 15/021,047 filed Mar. 10, 2016 (abandoned),which is a U.S. National Phase application under 35 U.S.C. § 371 ofInternational Application No. PCT/IB2014/064361 filed on Sep. 10, 2014,which claims the benefit of U.S. Provisional Application No. 61/884,178filed on Sep. 30, 2013. These applications are hereby incorporated byreference in their entireties.

BACKGROUND Technical Field

This disclosure relates to medical instruments and more particularly toshape sensing optical fibers in medical applications.

Description of the Related Art

Optical shape sensing (OSS) is a technology that permits accuratethree-dimensional (3D) reconstruction of a shape of a fiber along itsentire length. Integrating the fiber into an OSS enabled instrumentrequires coupling the fiber to the instrument such that any movement ofthe device can be reconstructed with respect to a fixed frame ofreference. Having a fixed or static launch region is needed since thefixed region provides a search template for a reconstruction algorithmto perform correlation and to match a reference to sample data. Thereconstruction initializes after this fixed region. The fixed regionalso defines the frame of reference (0,0,0) for OSS and, in essence, thecoordinate system in the shape sensing space.

SUMMARY

In accordance with the present principles, a launch fixture for opticalshape sensing (OSS) includes a first fixation device configured toreceive and secure an optical fiber. A fiber storage area is configuredto receive and maintain the optical fiber within specified dimensions. Asecond fixation device is configured to receive and secure a flexibleOSS enabled instrument. A launch region is configured to receive andmaintain the optical fiber in a known geometric configuration beforeentering the second fixation device. A feature is provided for aligningand coupling to a launch fixture base, which is configured to secure thelaunch fixture.

An optical shape sensing (OSS) system includes a launch fixture baseconfigured to be connected to a support structure, and a launch fixtureconfigured to be secured on the launch fixture base by at least onefeature for aligning and coupling the launch fixture base to the launchfixture. The launch fixture includes a first fixation device configuredto receive and secure an optical fiber; a fiber storage area configuredto receive and maintain the optical fiber within specified dimensions; asecond fixation device configured to receive and secure a flexible OSSenabled instrument; and a launch region configured to receive andmaintain the optical fiber in a known geometric configuration beforeentering the second fixation device.

A method for optical shape sensing (OSS) includes providing (502) alaunch fixture having a first fixation device configured to receive andsecure an optical fiber, a fiber storage area configured to receive andmaintain the optical fiber within specified dimensions, a secondfixation device configured to receive and secure a flexible OSS enabledinstrument, a launch region configured to receive and maintain theoptical fiber in a known geometric configuration before entering thesecond fixation device, and at least one feature for aligning andcoupling to a launch fixture base, which is configured to secure thelaunch fixture; and sensing a shape of the optical fiber.

The launch fixture may include features for aligning and coupling thelaunch fixture to a launch fixture base, which is configured to securethe launch fixture.

Alternatively, a docking device may be provided for securing one or morelaunch fixtures onto the launch fixture base whereby the docking devicemay serve as a bridge between a sterile zone and a non-sterile zone. Thedocking device may include one or more launch fixture slots on one sideof the docking device, or one or more launch fixture slots on each oftwo opposing sides of the docking device.

These and other objects, features and advantages of the presentdisclosure will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

This disclosure will present in detail the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a block/flow diagram showing a shape sensing system whichemploys a launch fixture with controlled fiber positioning in accordancewith one embodiment;

FIG. 2 is a perspective view of a launch fixture with controlled fiberpositioning in accordance with one embodiment;

FIG. 3 is a perspective view of a launch fixture base configured tosecure one or more launch fixtures in accordance with one embodiment;

FIG. 4 is a perspective view showing a plurality of stacked launchfixtures with controlled fiber positioning in accordance with oneembodiment;

FIG. 5 is a side view of a launch fixture base rack for storing aplurality of launch fixtures in accordance with one embodiment;

FIG. 6 is a perspective view of a launch fixture for handling aplurality of shape sensing devices with controlled fiber positioning inaccordance with another embodiment;

FIG. 7 is a perspective view of a modular launch fixture withattachable/detachable modules in accordance with one embodiment;

FIG. 8A is a side view showing a sterile boundary between a launchfixture and a launch fixture base in accordance with one embodiment;

FIG. 8B is a top view showing an open launch fixture with a partitionedsterile boundary between distal and proximal portions of the launchfixture in accordance with one embodiment;

FIG. 9 is a top view of a rail for conveying a launch fixture base inaccordance with one embodiment;

FIG. 10 is a flow diagram showing a method for optical shape sensing inaccordance with an illustrative embodiment;

FIG. 11 is a block diagram showing a shape sensing system which employslaunch fixture(s) with controlled fiber positioning and a docking devicefor securing launch fixture(s) to a launch fixture base in accordancewith one embodiment;

FIG. 12A is a side view of the shape sensing system of FIG. 11 deployedin an operating environment in accordance with one embodiment;

FIG. 12B is a perspective view of the optical fiber of FIG. 12A.

FIGS. 13A and 13B are views of the shape sensing system of FIG. 11relative to a patient in an operating environment in accordance with oneembodiment.

FIGS. 14A and 14B are perspective views of a launch fixture withcontrolled fiber positioning in accordance with one embodiment;

FIG. 14C is a view of a fiber clamp of the launch fixture of FIGS. 14Aand 14B in accordance with one embodiment;

FIG. 15A-15C are perspective views of the launch fixture of FIGS. 13Aand 13B secured onto a launch fixture base via a docking device inaccordance with one embodiment;

FIG. 16 is a perspective view of a launch base cover claim in accordancewith one embodiment;

FIG. 17 is a perspective view of a docking clamp of the launch fixturebase in accordance with one embodiment;

FIGS. 18A-18C are a perspective view and a side view, respectively, ofsupport clamp in accordance with one embodiment;

FIGS. 19A-19C are a perspective view and exploded views, respectively ofa connection box in accordance with one embodiment; and

FIGS. 20A-20E are views of the shape sensing system employing two setsof launch fixtures relative to a patient in an operating environment inaccordance with one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In accordance with the present principles, a launch fixture and launchfixture base design provide for rapid attachment and detachment of oneor more optical shape sensing (OSS) enabled flexible instrument(s) to afixed reference in an operating theatre. The fixture can also bedisposed in a transition zone between sterile and non-sterile regions inan operating theatre, allowing for the rapid exchange of OSS-enableddevices by personnel in the non-sterile region without breaking thesterile barrier.

In one embodiment, the launch fixture ensures that the geometricrelationship between adjacent instrument frames of reference and thelaunch fixture base frame of reference are known, so that eachinstrument is automatically registered to the launch fixture base onceconnected. Given that the launch fixture base is registered to a patientor imaging frame of reference prior to a beginning of the procedure,this architecture permits each instrument to be rapidly deployed in aco-registered frame of reference. In addition, the overall footprint ofthe instruments in the operating theatre can be minimized through theuse of vertical, horizontal, or angled stacking.

During clinical use, it is likely that multiple shape sensing enabledinstruments will be deployed and exchanged during a given procedure. Inone system architecture, each instrument could be attached to theoperating table using a unique launch fixture base. However, as thenumber of instruments employed increases, a number of componentsattached to the table would increase accordingly. This would hinderclinician movement around the table and result in a cluttered operatingfield. In addition, since the OSS fiber within each instrument willreconstruct the shape of the instrument with respect to a frame ofreference located within that instruments' launch fixture, eachinstrument would need to be individually registered to thepatient/imaging system frame of reference.

In accordance with the present principles, the footprint of theinstrument launch fixtures within the operating theatre is minimized, aswell as the time spent registering devices. The launch fixture andlaunch fixture base permit rapid exchange of devices while maintaining adefined geometric relationship between frames of reference so thatre-registration is not required. This fixed frame of reference isincluded within a launch fixture, which is coupled to a proximal end ofthe flexible instrument and includes design features which allow thefiber to be safely and securely coupled to the instrument. By attachingthis launch fixture rigidly to the launch fixture base, which may itselfbe rigidly connected to the operating table, needed transformationsbetween an instrument frame of reference and patient/imaging frames ofreference can be computed. Thus, the reconstructed shape of theinstrument can be overlaid on pre- and intra-operative images and usedfor navigation purposes.

It should be understood that the present invention will be described interms of medical instruments; however, the teachings of the presentinvention are much broader and are applicable to any fiber optic shapesensed instruments. In some embodiments, the present principles areemployed in tracking or analyzing complex biological or mechanicalsystems. In particular, the present principles are applicable tointernal tracking procedures of biological systems, procedures in allareas of the body such as the lungs, gastro-intestinal tract, excretoryorgans, blood vessels, etc. The elements depicted in the FIGS. may beimplemented in various combinations of hardware and software and providefunctions which may be combined in a single element or multipleelements.

The functions of the various elements shown in the FIGS. can be providedthrough the use of dedicated hardware as well as hardware capable ofexecuting software in association with appropriate software. Whenprovided by a processor, the functions can be provided by a singlededicated processor, by a single shared processor, or by a plurality ofindividual processors, some of which can be shared. Moreover, explicituse of the term “processor” or “controller” should not be construed torefer exclusively to hardware capable of executing software, and canimplicitly include, without limitation, digital signal processor (“DSP”)hardware, read-only memory (“ROM”) for storing software, random accessmemory (“RAM”), non-volatile storage, etc.

Moreover, all statements herein reciting principles, aspects, andembodiments of the invention, as well as specific examples thereof, areintended to encompass both structural and functional equivalentsthereof. Additionally, it is intended that such equivalents include bothcurrently known equivalents as well as equivalents developed in thefuture (i.e., any elements developed that perform the same function,regardless of structure). Thus, for example, it will be appreciated bythose skilled in the art that the block diagrams presented hereinrepresent conceptual views of illustrative system components and/orcircuitry embodying the principles of the invention. Similarly, it willbe appreciated that any flow charts, flow diagrams and the likerepresent various processes which may be substantially represented incomputer readable storage media and so executed by a computer orprocessor, whether or not such computer or processor is explicitlyshown.

Furthermore, embodiments of the present invention can take the form of acomputer program product accessible from a computer-usable orcomputer-readable storage medium providing program code for use by or inconnection with a computer or any instruction execution system. For thepurposes of this description, a computer-usable or computer readablestorage medium can be any apparatus that may include, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device) or apropagation medium. Examples of a computer-readable medium include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk—read only memory (CD-ROM), compactdisk—read/write (CD-R/W), Blu-Ray™ and DVD.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1 , a system 100 for opticalshape sensing is illustratively shown in accordance with presentembodiments. System 100 may include a workstation or console 112 fromwhich a procedure is supervised and/or managed. Workstation 112preferably includes one or more processors 114 and memory 116 forstoring programs and applications. Memory 116 may store an opticalsensing module 115 configured to interpret optical feedback signals froma shape sensing device or system 104. Optical sensing module 115 isconfigured to use the optical signal feedback (and any other feedback,e.g., electromagnetic (EM) tracking) to reconstruct deformations,deflections and other changes associated with a medical device orinstrument 102 and/or its surrounding region. The medical device 102 mayinclude a catheter, a guidewire, a probe, an endoscope, a robot, anelectrode, a filter device, a balloon device, or other medicalcomponent, etc.

The shape sensing system 104 on device 102 includes one or more opticalfibers 126 which are coupled to the device 102 in a set pattern orpatterns. The optical fibers 126 connect to the workstation 112 throughcabling 127. The cabling 127 may include fiber optics, electricalconnections, other instrumentation, etc., as needed.

Shape sensing system 104 with fiber optics may be based on fiber opticBragg grating sensors. A fiber optic Bragg grating (FBG) is a shortsegment of optical fiber that reflects particular wavelengths of lightand transmits all others. This is achieved by adding a periodicvariation of the refractive index in the fiber core, which generates awavelength-specific dielectric mirror. A fiber Bragg grating cantherefore be used as an inline optical filter to block certainwavelengths, or as a wavelength-specific reflector.

A fundamental principle behind the operation of a fiber Bragg grating isFresnel reflection at each of the interfaces where the refractive indexis changing. For some wavelengths, the reflected light of the variousperiods is in phase so that constructive interference exists forreflection and, consequently, destructive interference for transmission.The Bragg wavelength is sensitive to strain as well as to temperature.This means that Bragg gratings can be used as sensing elements in fiberoptical sensors. In an FBG sensor, the measurand (e.g., strain) causes ashift in the Bragg wavelength.

One advantage of this technique is that various sensor elements can bedistributed over the length of a fiber. Incorporating three or morecores with various sensors (gauges) along the length of a fiber that isembedded in a structure permits a three dimensional form of such astructure to be precisely determined, typically with better than 1 mmaccuracy. Along the length of the fiber, at various positions, amultitude of FBG sensors can be located (e.g., 3 or more fiber sensingcores). From the strain measurement of each FBG, the curvature of thestructure can be inferred at that position. From the multitude ofmeasured positions, the total three-dimensional form is determined.

As an alternative to fiber-optic Bragg gratings, the inherentbackscatter in conventional optical fiber can be exploited. One suchapproach is to use Rayleigh scatter in standard single-modecommunications fiber. Rayleigh scatter occurs as a result of randomfluctuations of the index of refraction in the fiber core. These randomfluctuations can be modeled as a Bragg grating with a random variationof amplitude and phase along the grating length. By using this effect inthree or more cores running within a single length of multi-core fiber,the 3D shape and dynamics of the surface of interest can be followed.

In one embodiment, workstation 112 includes an image generation module148 configured to receive feedback from the shape sensing device 104 anddisplay position/shape for the shape sensing device 104 within a volume131. An image 134 of the shape sensing device 104 within the space orvolume 131 can be displayed on a display device 118. Workstation 112includes the display 118 for viewing internal images of a subject(patient) or volume 131 and may include the image 134 as an overlay orother rendering of shapes of the shape sensing device 104. Display 118may also permit a user to interact with the workstation 112 and itscomponents and functions, or any other element within the system 100.This is further facilitated by an interface 120 which may include akeyboard, mouse, a joystick, a haptic device, or any other peripheral orcontrol to permit user feedback from and interaction with theworkstation 112.

A launch fixture 150 includes mechanical features 152 configured toensure that the fiber 126 or the shape sensing device 104 can be coupledto the elongate instrument 102 such that the fiber measures changes inshape of the instrument with respect to a fixed frame of reference. EachOSS enabled instrument 102 employs a launch fixture (150) to define afixed frame of reference which may be registered to a patient frame ofreference 136, or imaging frame of reference 138, or both.

A launch fixture base 160 is rigidly attached to a fixed feature orsupport structure 162 in the operating theatre (e.g., an operating tableor similar structure) which allows for multiple launch fixtures 150 (andhence multiple OSS enabled instruments 102) to be attached andco-registered to the patient frame of reference 136, or imaging frame ofreference 138, or both. In another embodiment, there is more than oneOSS enabled instrument 104 within a single fixture 150. The launch andcoordinate systems of these fibers are known with respect to each otheras well as the patient and imaging frames of reference 136, 138, thusallowing faster use when these devices are used in conjunction, such as,e.g., a guidewire and a catheter being used together.

In another embodiment, the launch base 160 and/or the launch fixture 150may include features to monitor the use of the launch fixture 150 anddevices 102. For example, a scan mechanism 135 may be incorporated intothe base 160 or fixture 150 (e.g., a radiofrequency scanner) thatautomatically detects which OSS enabled instrument 102 is being used.Mechanism 135 may monitor a number of times a same device is clipped in(to monitor or prevent) more than one-time use of the device 102. Themechanism 135 may include an indicator (e.g., a light, counter or colorstrip) that indicates an end of life (after say 1000 devices have beenmounted) of the launch base 150 and alert the service engineer formaintenance. Other configurations for mechanism 135 are alsocontemplated.

In one embodiment, a position of the launch fixture base 160 (and/orlaunch fixture 150) with respect to an imaging system 110 is trackedusing an appropriate sensor 137 (position encoder, magnetic tracking,etc.). This provides easy registration to the imaging system 110.

Another feature of the launch fixture 150 is that it may lay in a zoneseparating a sterile region 152 (inside the dashed box) and anon-sterile region 154 in a surgical room. A sterile barrier 163 may beprovided such that a proximal portion of device 150 (in region 154) isnon-sterile and a distal portion of the device 150 (in region 154) is inthe sterile region, which includes a mechanism (a barrier or sealedpartition within the device 150) for not contaminating the sterileregion 152 in an operating room. In one possible workflow, by allowingthe non-sterile personnel such as a nurse to perform the proximalconnections to a laser and clip on the launch fixture 150 to the launchbase 160 and handing a protected OSS-enabled instrument 104 to thesterile personnel, the launch fixture 150 allows use of OSS-enableddevices 104 without breaking the sterile barrier. In another possibleworkflow, the launch base 160 is also sterile and connects to thesupport 162 over a sterile drape 155. This combination also allows forthe launch fixture 150 to be employed to enable the use of OSSinstruments 102 without breaking the sterile barrier 163.

Referring to FIG. 2 , a launch fixture 150 suitable for coupling an OSSfiber device 104 to a flexible instrument 102 in a controlled manner isillustratively shown. The launch fixture 150 includes a fixation pointor device 172 to clamp the optical fiber 104 and its protective tubing,housing, or similar structure 173 in place into the fixture 150. Adefined path 174 is formed to permit excess fiber to be included withinthe fixture 150 while not exceeding a specified minimum bend radius.This path 174 may also include features which allow for automaticalignment of the polarization of the OSS laser system to be performedwhile the instrument is connected to the OSS console. When a fiberundergoes a tight bend the index of refraction experienced by the lightthrough that bend will vary depending on the orientation of the light.To mitigate these birefringence effects, optical shape sensingmeasurements are commonly performed with multiple light polarizations.One technique to optimally select (or ‘align’) those polarization statesis to use the measured optical response through a known feature, such asa bend. An example of such a feature is a defined path 174 withsufficient curvature to induce birefringence effects in the fiber. Thesebirefringence effects provide unique features in the measured opticalsignal that can be used for automatic alignment of the systempolarization. Ideally, this curvature will have a tight radius toamplify the birefringence effects and thus allow for a more uniquefeature upon which to perform alignment. This alignment feature canexist prior to a launch region 176 within the launch fixture 150.

The launch region 176 permits the OSS fiber device 104 to be physicallyattached to the fixture 150 in a defined manner (e.g., straight or witha known geometry). The path prior to the launch region 176 may havefeatures 177 which ensure the fiber enters the launch region 176 in acontrolled manner (e.g., pegs, radiused features, etc.). A path 178(which may be included in path 174) acts as a buffer, or service loop,to allow for curvature induced path length changes to be accommodated bythe fiber repositioning within the fixture 150 while not exceeding aspecified minimum bend radius. Such a service loop may take severaldifferent forms, e.g., the service buffer loop of path 178 may include a90 degree, 360 degree bend, etc. instead of or in addition to the 180degree bend depicted in FIG. 2 . A gap distance 171 of the path 178provides slack for manipulating the fiber but protects the fiber fromexceeding the minimum bend radius.

A fixation point or device 180 clamps the flexible instrument 102 to thefixture 150 and surface curvatures/fillets 182 ensure that thetransition between the fixture 150 and the flexible instrument 102occurs without negatively effecting the strain measurement of the OSSfiber 104. Mechanical design features 184 allow the fixture 150 to bereproducibly connected to the launch fixture base 160 (FIG. 1 ), orother launch fixtures in a known geometric manner. Screws, magnets,snap-fits, clips, pegs, or similar mechanisms can be employed to achievethis. Feature or features 184 with known geometry, curvature or shape,may be employed for registering the device 102 to other OSS-enableddevices, the patient and the imaging frame of reference 136, 138. Thefeature(s) 184 may be employed for the dual purpose of attaching thefixture 150 to the launch base 160 and attaching fixtures 150 to eachother. The feature(s) 184 may be directional shaped (e.g., square,triangle, etc.) to ensure that the base 160 and the fixtures 150 areproperly aligned relative to one another.

The launch fixture 150 is depicted in an open configuration in FIG. 2 .A lid (not shown) can be employed to cover the open launch fixture 150or another launch fixture (not shown) may nest or be coupled to thelaunch fixture 150. The lid or additional launch fixture (150) may bescrewed or otherwise connected into place to both clamp the componentsinto place (on the base 160) and to protect the fiber from theenvironment by employing features 186. Feature 186 may include similarmechanism and described for features 184.

An additional feature of the launch fixture 150 includes a defined path179 for the fiber distal from the launch region 176 which can be used tocorrect for any rotation of the launch region during use. In practice,the fiber is clamped in place at the launch region 176; however, in somecircumstances the fiber can ‘rotate’ within the clamp and thus anyregistrations can become inaccurate. By having a known shape distal fromthe launch region, this rotation can be corrected for. The defined path179 may include a curved path in two or three dimensions, e.g., asemi-circle, compound curves (e.g., sinusoid), an arc, a coiled shape,etc. The defined path 179 may be included distally to the launch region176 within the launch fixture 150 or may be included as a detachablemodule 169 that connects to the launch fixture (as depicted in FIG. 2 ).

Referring to FIG. 3 , a launch fixture base 160 is shown in accordancewith one illustrative embodiment. The launch fixture base 160 includesfeatures 190, such as holes, pegs, detents, protrusions, etc. configuredto rigidly attach to a fixed frame of reference within the operatingtheatre (e.g., the operating table or the like). The launch fixture base160 includes the ability to be reproducibly connected to one or morelaunch fixtures 150 with a known geometric relationship. This mayinclude features 192, such as holes, pegs, detents, protrusions, etc.configured to permit easier connection and fixation of the launchfixture(s) 150 or a lid on the launch fixture(s) 150.

Referring to FIG. 4 , three launch fixtures 150, 151 and 153 areconnected to a launch fixture base 160 which is, in turn, connected toan operating table (not shown) via steel rods and support structure 163and appropriate clamps, etc. In this architecture, the transformationsbetween the frames of reference of the individual launch fixtures (andhence the flexible instruments 102 connected to the launch fixtures 150,151, 153) and the launch fixture base 160 are known. Assuming atransformation between the launch fixture base 160 and the patient orimaging system frame of reference is known, then different launchfixtures 150, 151, 153 can be connected to the launch fixture base 160and used for imaged guided navigation without requiring are-registration step. The known geometric relationship between eachlaunch fixture 150, 151, 153 and the launch fixture base 160 can be usedto minimize time spent registering each device to the patient/imagingsystem frame of reference.

In one embodiment, launch fixtures 150, 151, 153 can be rigidly attachedto the launch fixture base 160 using threaded bolts 188. A lid 165 maybe employed as well and secured together with fixtures 150, 151, 153.For example, additional launch fixtures 151, 153 can be attached to theinitial launch fixture 150 with lid 165 using longer bolts. In otherembodiments, magnets, clips, snap fits or similar rapid attachmentcomponents may be employed instead of bolts to attach and detach thelaunch fixture(s) from each other and the launch fixture base 160. Quickconnect or magnetic attachment mechanisms (e.g., snap togetherarrangements, clamps, clasps, tongue and groove, etc.) may be employedto make quick and secure but releasable connections between the base 160and fixtures 150, 151, 153 and between fixtures 150, 151, 153. Thegeometric relationship between adjacent launch fixtures 150, 151, 153(and hence their instrument frames of reference) and the launch fixturebase 160 can be used to ensure that re-registration of multiple devicesis not required as devices are exchanged during a procedure. Inaddition, by locating the fixtures 150, 151, 153 and base 160 at asingle location clutter is reduced and an organized and efficientoperating theater is maintained.

Referring to FIG. 5 , in another embodiment, launch fixtures 150′ coupleto a launch fixture base 160′ independently (e.g., not stacked on eachother). Examples of such an embodiment include a rack-style base orsimilar architecture where the fixtures can be stacked horizontally,vertically or angled with respect to an operating table or otherreference structure.

In one embodiment, connection features 163 may include different shapesfor receiving different types of OSS enabled devices 102. For example, asquare, triangle, circle, etc. feature 163 may be employed to limit thetype of OSS enabled device 102 connected to the launch fixture 150′. Forexample, a guide wire may include a square connector, a catheter mayinclude a round connector and an endoscope may include a triangularconnector.

Referring to FIG. 6 , in another embodiment, similar to that launchfixture 150, a launch fixture 250 is shown capable of coupling two OSSfibers 104 to two flexible instruments 102 within a single fixture 250.An entrance point 254 for one fiber and an exit point 255 for oneflexible instrument 102 are depicted. An entrance point 256 for onefiber and an exit point 257 for another flexible instrument 102 are alsodepicted. In this embodiment, if two instruments 102 are employed withinthe single fixture 250, one instrument 102 may use a buffer, or serviceloop 252 and, the other instrument 102 may not employ the service loop252. However, a service loop may be provided for both instruments inother embodiments. Other embodiments may employ a single fixture with agreater number of flexible instruments. A fiber path 258 may be employedfor automatic alignment of light source polarization states, asdescribed above.

Referring to FIG. 7 , a modular launch fixture 350 is shown inaccordance with one embodiment. The fixture 350 illustratively includesselected elements or features needed to couple an OSS fiber to aflexible instrument in a controlled manner. The launch fixture 350 inthis particular embodiment adopts a modular approach to attaching eachof a plurality of elements described above to a rail system or launchfixture base 362. This rail 362 can be attached to an operating tableand then registered to the patient and/or imaging system frame ofreference.

The launch fixture 350 illustratively includes a launch region module352, a buffer or service loop module 354, an excess fiber path module356, a fiber boot clamp module 358, and a clamp module 360 for theflexible instrument 102. Other modules 364 may be included. The modules352, 354, 356, 358, 362, 364 are individually separable from the launchfixture base 360 and adjacent modules. The modular embodiment of thelaunch fixture 350 may include multiple flexible instruments and/orstackable launch fixtures, each with one or more flexible instruments.The fibers in each module may include optical connectors so that modulescan be easily changed out as needed.

Referring to FIG. 8A, a protective layer 380 (e.g., a plastic film,sterile drape or the like) is disposed between the launch base 160 andthe launch fixture 150, allowing a sterile device within a protectedplastic 382 to clip on the non-sterile launch-base 160 while stillhaving the packaging that maintains sterility. Others arrangements arealso contemplated.

In another embodiment, the launch fixture base 160 can be multi-use,sterilizable and connect over a sterile drape 383. The launch fixture150 can be connected to the sterile launch fixture base 160 thusallowing the OSS device to be used within the sterile field.

Referring to FIG. 8B, a protective partition 386 (e.g., a stainlesssteel wall) with sealed orifices 388 is disposed in the launch fixture150, allowing a sterile device on a distal side (with instrument 102)and a non-sterile device on a proximal side (with fiber 104). Othersarrangements are also contemplated.

Referring to FIG. 9 , in another embodiment, the launch fixture base 160is coupled to a rail 402 or other structure such that the OSS enableddevice 102 could be used for entering a body 131 at different locations,such as femoral access versus carotid access. The launch fixture base160 could be repositioned at preset states or locations 404, 406 andlock into place by a clamp 408 or other securing device. The positions,orientations and transforms of the base 160 at these locations 404, 406with respect to other locations would be known and thus, registeringmultiple OSS devices 102 would be straightforward and simple. In oneembodiment, the launch fixture 150 and/or launch fixture base 160 may berobotically actuated and manipulated to different positions with orwithout the rail 402 (the rail 402 may also be robotically positioned).Translation and rotation of the rail 402, the launch fixture 150 and/orlaunch fixture base 160 may be provided robotically for medicalprocedures (e.g., endovascular, endoluminal and/or orthopedicapplications, etc.) or other applications. In another embodiment,translation along the rail 402 may be performed manually, and thetransformations to the patient or imaging coordinate systems, or both,can be calculated by measuring the position along the rail 402 using aposition sensing device (potentiometer, optical tracker, etc.). If arobot is employed, the fixtures 150 and base 160 may be registered tothe robotic coordinate system.

Referring to FIG. 10 , a method for optical shape sensing (OSS) includesproviding a launch fixture for handling optical fiber in a controlledmanner, in block 502. The launch fixture includes a first fixationdevice configured to receive and secure an optical fiber, a fiberstorage area configured to receive and maintain the optical fiber withinspecified dimensions, a second fixation device configured to receive andsecure a flexible OSS enabled instrument, a launch region configured toreceive and maintain the optical fiber in a known geometricconfiguration before entering the second fixation device, and at leastone feature for aligning and coupling to a launch fixture base, which isconfigured to secure the launch fixture. The launch fixture may includeother features as well, e.g., a defined path which can be used tocorrect for rotation of the fiber launch region (as described above).

In block 504, the launch fixture is equipped with at least one OSSfiber, which is initially secured in the first fixation device, and atleast one OSS enabled device, which is secured in the second fixationdevice. The OSS fiber is stowed in buffer or loop area configured tomaintain minimum dimensions requirements to the fiber and to providesome slack for accommodating operational movement of the fiber withoutexceeding the requirements. In block 506, the launch fixture is securedto a launch fixture base. The launch fixture base may be secured to anoperating table, a rail system, robotic instrument, imaging system, etc.In one embodiment, the launch fixture base may be actuated to differentposition within an operating theater.

In block 508, other launch fixtures are stacked on the launch fixtureand/or a lid is placed over the launch fixture. In block 510, the launchfixture or fixtures and/or fixture base are registered to at least oneof a patient frame of reference and an imaging frame of reference,although other references may be employed. In block 512, a sterilebarrier may be employed through the launch fixture(s), between thelaunch fixture and the launch fixture base or between modules of amodular launch fixture. In block 514, the flexible OSS enabledinstrument is employed to sense a shape of the optical fiber.

Referring to FIG. 11 , in practice, the present disclosure provides acapability of using a fixation assembly of the present disclosure on oneside or both sides of an operating table, while minimizing theconstraints on the “free” part of the optical cables fixed to the launchfixture (i.e., the portion of the cable bridging the launch fixture tothe portion of the OSS enabled instrument to be inserted in the patientbody). Such constraints may appear if the bending of these cables is tooimportant, in general or locally, or if the cables are twisted etc.,which could lead to performance loss in general (e.g., a problem ofregistration or a problem of undesired movement of the cables duringoperation). Thus, it is desirable to minimize those constraints whilehaving the possibility to mount the fixture assembly one or other sideof the operating table.

To thereby minimize the constraints, the embodiment of the presentdisclosure as shown in FIG. 11 provides an additional component to thelaunch assembly 600 in the form of a docking device 670 serving as anintermediate piece between an X number of launch fixatures 650, X≥1 anda launch fixture base 660 for securing the launch fixture(s) 650 ontothe launch fixture base 660.

In practice, a purpose of docking device 670 is to provide a sterilefixation for the launch fixture(s) 650. More particularly as will befurther described in the present disclosure, a sterile patient drape(not shown) may be placed on top of the launch fixture base 660,whereupon the docking device 670 is placed. Moreover, as will be furtherdescribed in the present disclosure, a design of the docking device 670may be reversible and ensures the exit angle of the launch reduces theissues as mentioned above. Each launch fixture 650 is an embodiment ofthe launch fixtures 150 of FIG. 1 , whereby each launch fixture 650receives and secures an optical fiber 626 and a flexible OSS instrument602 having optical fiber embedded therein. For this embodiment, eachoptical fiber 626 is connected to a connector box 690 to an interrogator(not shown).

In practice, as will be exemplary shown in more detail herein, dockingdevice 670 may have one or more sides connectable to the launch fixturebase 660 whereby the launch fixtures 650 are installable into opposingside(s) of docking device 670.

Also in practice, as will be exemplary shown in more detail herein,docking device 670 may be detachable connectable to launch fixture base660 (e.g., clipped thereto) and docking device 670 may include fixingelement(s) (not shown) arranged on one side or on two opposing sides ofthe docking device 670 to detachably fix the docking device 670 to thelaunch fixture base 660.

In practice, for embodiments having fixing element(s) (not shown) on twoopposing sides of the docking device 670, the fixing elements must bearranged for alignment with the launch fixture base 660 for either side.

More particularly, in one embodiment, a geometry and a location of thesefixing element(s) are symmetrical with respect to a transversal plane ofthe docking device 670 (e.g., transversal plane being perpendicular toan operating table) such that the docking device 670 can still be fixedto the launch fixture base 660 even after a 180° rotation about an axisperpendicular to the main axis of the operating table (i.e., an “upsidedown-ability” fixation). Alternatively, a geometry and a location ofthese fixing element(s) may be non-symmetrical with respect to atransversal plane of the docking device 670 (e.g., a rotationallysymmetry around a short axis of an operating table plane), and ageometry and a location of these fixing element(s) may be symmetricalwith respect to a transversal plane of the docking device 670 without arotational symmetrical around the axis perpendicular to the main axis ofthe operating table.

Further in practice, as will be exemplary shown in more detail herein,docking device 670 may employ one or more connecting through-slots (notshown) to receive the launch fixture(s) 650, with a symmetry regardingthe geometry of these connecting slots with respect to a longitudinalplane (e.g., longitudinal plane being parallel to an operating table),this symmetry involves in particular symmetry of the locations andgeometries of connecting protrusions extending from the internal wallsof the slots, in order to be able to clip the launch fixture(s) 650 bothfrom the top and from the bottom of the connecting slots (and the samefor the connectors provided on top of the launch fixture base 660 ifany).

In one embodiment, as will be exemplary shown in more detail herein, theconnecting slots are angled with respect to the main axis of anoperating table, in such a way that the mechanical constraints on theoptical fiber(s) 626 clamped to the launch fixture(s) 650 are minimized.The rotation of the docking device 670 as previously explained allowskeeping the angle of the connecting slots with respect to the main axisof the operating table to thereby minimize constraints on optical fibers626 if the launch fixture base 660 and docking device 670 are positionedon the other side of the operating table without changing the positionof the patient on the operating table. This feature is advantageous forsurgeons/clinicians.

Optionally in practice, a label may be provided on both main surfaces ofthe docking device 670 indicating the right positioning of the dockingdevice 670 with respect to a position of a patient (e.g. that could be aschematic representation of the patient: position of the head), whichmay help the technician (or the surgeon) to position the docking device670 (or the patient) in a correct position with respect to the positionof the patient (or to the position of the docking device 670).

Also optionally in practice, the docking device 670 may be provided as asterile component, and the design of the launch fixture base 660 mayallow for a drape (not shown) to be arranged between the launch fixturebase 660 and the docking device 670 while still fixing the dockingdevice 670 properly, whereby the sterile instruments 602 would beconnected to a corresponding launch fixture 650 to a sterile dockingdevice 670. A tether (not shown) leading from a launch fixture 650 tothe non-sterile connector box 690 may be used to bridge the sterilebarrier.

Further optionally in practice, at least 2 indicators of differentcolors, one color provided to a launch fixture 650 of one type ofinstrument 602 (e.g., a catheter) and one color provided to anotherlaunch fixture 650 of a different type of instrument 602 (e.g., aguidewire) may be used as the respective virtual representations of theinstruments 602 (e.g., catheter & guidewire) on a display (not shown).The actual indicators being located on the launch fixture(s) to beeasily seen by the user during operation and while he/she is watchingthe display.

Additionally optionally in practice, a marker may be provided on a railof an operating table to position the launch fixture base 660 at theright position to minimize strains on the optical fiber 626. Severalmarkers may be provided depending on the length of the optical fibers626.

Even further in practice, as will be exemplary shown in more detailherein, each launch fixture 650 may employ a radio frequencyidentification (RFID) tag identifying a type of OSS enabled instrument602 (e.g., a catheter or a guidewire) secured by the launch fixture 650and launch fixture base 660 may employ a RFID antenna to thereby sensethe RFID tag(s) of the launch fixture(s) 650. Furthermore, a connectorof each launch fixture 650 may employ a RFID tag identifying thatparticular launch fixture 650 and connector box 690 may employ a RFIDantenna to thereby sense the RFID tag(s) of the connectors.

In one embodiment, connection box 690 includes a RFID controllerincluding an RFID antenna for sensing the RFID tag(s) of the fixtureconnectors to thereby distinguish between the launch fixture(s) 650.Additionally, the RFID controller may be in communication with the RFIDantenna of the launch fixture base 660 thereby support a displayed colorrepresentation of the type of OSS enabled instrument 602 for each launchfixture 650.

Various embodiments of launch fixture 650, launch fixture base 660 anddocking device 670 as shown in FIGS. 12-22 will now be described herein.

Referring to FIG. 12A, a launch fixture base 660 a is connected via atable clamp 680 onto an operating table 662, and a docking station 670 asecures a launch fixture 650 a onto launch fixture base 660 a. Launchfixture 650 a receives and secures an optical fiber 626 a and a flexibleOSS instrument 602 a. The optical fiber 626 a is connectable to aconnector box 690 a for a signal connection to an interrogatorworkstation 612.

Referring to FIG. 12B, a free section 627 of optical fiber 626 a has oneend within a connector 691 and another end received and secured withinlaunch fixture 650 a. A torque absorbing section 628 of optical fiber626 a (aka a joining section) has one end secured within launch fixture650 a and another end adjacent with an in-body section 629 of opticalfiber 626 a. A torque absorbing section 628 of optical fiber 626 adecouples rotation of in-body section 629 from launch fixture 650 asfixed by the docking device 670 a.

Referring to FIGS. 13A and 13B, a representation of FIG. 12A is showndocking device 670 a detachably connected to launch fixture base 660 a(e.g., clipped thereto) and docking device 670 a including fixingelement(s) (not shown) arranged on one side of the docking device 670 ato detachably fix the docking device 670 a to the launch fixture base660. A geometry and a location of these fixing element(s) aresymmetrical with respect to a transversal plane of the docking device670 a (e.g., transversal plane being perpendicular to an operating table662) such that the docking device 670 a can still be fixed to the launchfixture base 660 a even after a 180° rotation about an axisperpendicular to the main axis of the operating table 662 (i.e., an“upside down-ability” fixation).

Docking device 670 a employs three (3) connecting through-slots toreceive three (3) launch fixtures 650, with a symmetry regarding thegeometry of these connecting slots with respect to a longitudinal plane(e.g., longitudinal plane being parallel to an operating table 662),this symmetry involves in particular symmetry of the locations andgeometries of connecting protrusions extending from the internal wallsof the slots, in order to be able to clip the launch fixture(s) 650 aboth from the top and from the bottom of the connecting slots (and thesame for the connectors provided on top of the launch fixture base 660 aif any).

The connecting slots are angled with respect to the main axis of anoperating table 662, in such a way that the mechanical constraints onthe optical fibers 626 clamped to the launch fixtures 650 a areminimized. The rotation of the docking device 670 a as will in moreexplained herein allows keeping the angle of the connecting slots withrespect to the main axis of the operating table 662 to thereby minimizeconstraints on optical fibers 626 if the launch fixture base 660 a anddocking device 670 a are positioned on the other side of the operatingtable 662 without changing the position of the patient on the operatingtable 662. This feature is advantageous for surgeons/clinicians.

In practice, a docking device 670 may employ one or more connectingthrough-slots and docking device 670 includes a RFID reader per slot forreading a RFID tag of the launch fixture(s) 650.

Referring to FIGS. 14A and 14B, launch fixture 650 a has a housing 651and a docking interface 652.

Housing 651 includes a fixation device 653 configured to receive andsecure an optical fiber, a fiber storage area 654 configured to receiveand maintain the optical fiber within specified dimensions, a fixationdevice 656 configured to receive and secure a flexible OSS enabledinstrument, and a launch region 657 configured to receive and maintainthe optical fiber in a known geometric configuration before entering thesecond fixation device.

Launch region 657 includes three (3) shafts 658 a-658 c as shown in FIG.14C to clamp the optical fiber.

Docking interface 652 includes a series of slots 659 a-659 c forconnecting to a launch fixture slot of docking device 670 a.

Referring to FIGS. 15A-15C, the docking interface 652 of launch fixtures650 are inserted within launch fixture slots 671 a-671 c of dockingdevice 670 a. Each slot 671 a-671 c employs a base interface (e.g., baseinterfaces 673 b and 673 c shown in FIG. 15C) for interfacing with thedocking interfaces 652. Additionally, launch fixture base 660 a has anupright standing wall 661 and a base 662 for interconnecting withdocking device 670 a via fixing elements (not shown) between base 662and docking device 670 a.

Referring to FIG. 16 , the docking device 670 a may be provided as asterile component, and the design of the launch fixture base 660 a mayallow for a drape 700 to be arranged between the launch fixture base 660a and the docking device 670 a to form a bridge between a sterile zone700 and a un-sterile zone 701 while still fixing the docking device 670a properly. For this embodiment, the sterile instruments 602 would beconnected to a corresponding launch fixture 650 a to a sterile dockingdevice 670. A tether (not shown) leading from a launch fixture 650 a tothe non-sterile connector box 690 a (FIG. 11 ) may be used to bridge thesterile barrier formed by drape 700. Also, as shown in FIG. 17 , a clampforce applied by torsion spring 664 to have high force in clamp positionof docking device 670 a (FIG. 15B) on launch fixture base 680 a and theforce lowers when opening to thereby minimize damage to drape 700.

Referring to FIGS. 18A-18C, table clamp 680 employs a lever 681, aspring 682, an arm 683 and a stop 684. Lever 681 is operated to rotatearm 683 against the force of spring 682 to enable a positioning of arail 663 of operating table 662 between arm 683 and stop 684. Lever 681is released to enable the force of spring 682 to securely clamp rail 663between arm 683 and stop 684. In practice, the force needed to open thetable clamp 680 does not increase by using an optimized curve.

Referring to FIGS. 19A-19C, connector box 690 a has two (2) outlets 692a and 692 b for connector 691 (FIG. 12 ). As shown in a side view ofFIG. 19B, when inserted in an outlet 692 (e.g., outlet 692 a), connector691 includes a RFID 693 for identifying the type of instrument 602 (FIG.11 ). As shown in a rear view of FIG. 19C, outlets 692 a and 692 b and aRFID controller 694 are connected to interrogator workstation 612 (FIG.12A) via a series 693 of optical fibers and communication wire.

To facilitate an understanding of the reversible nature of a dockingdevice of the present disclosure, FIG. 20A shows a launch assembly 600 aand a launch assembly 600 b attached to opposing sides of operatingtable 662. As shown in FIGS. 20B-20E, a docking device 670 a of launchassembly 600 a is supporting three (3) launch fixtures 650 a-650 c, anda docking device 670 b of launch assembly 600 b is supporting three (3)launch fixtures 650 d-650 f.

The connecting slots 671 of the docking devices 670 are angled withrespect to the main axis of an operating table 662, in such a way thatthe mechanical constraints on the optical fiber(s) (not shown) clampedto the launch fixture(s) 650 will be minimized. As such, as shown inFIG. 20E, docking device 670 b is a rotation of docking device 670 athat allows keeping the angle of the connecting slots 671 with respectto the main axis of the operating table 662 to thereby minimizeconstraints on optical fibers (not shown) if the launch fixture base 660and docking device 670 are positioned on the other side of the operatingtable 662 without changing the position of the patient on the operatingtable 662. This feature is advantageous for surgeons/clinicians. Ininterpreting the appended claims, it should be understood that:

a) the word “comprising” does not exclude the presence of other elementsor acts than those listed in a given claim;

b) the word “a” or “an” preceding an element does not exclude thepresence of a plurality of such elements;

c) any reference signs in the claims do not limit their scope;

d) several “means” may be represented by the same item or hardware orsoftware implemented structure or function; and

e) no specific sequence of acts is intended to be required unlessspecifically indicated.

Having described preferred embodiments a launch fixture for opticalshape sensing (which are intended to be illustrative and not limiting),it is noted that modifications and variations can be made by personsskilled in the art in light of the above teachings. It is therefore tobe understood that changes may be made in the particular embodiments ofthe disclosure disclosed which are within the scope of the embodimentsdisclosed herein as outlined by the appended claims. Having thusdescribed the details and particularity required by the patent laws,what is claimed and desired protected by Letters Patent is set forth inthe appended claims.

1. An optical shape sensing (OSS) system, comprising: a launch fixtureconfigured to receive and secure an optical fiber within a flexible OSSenabled instrument, wherein the launch fixture comprises a dockinginterface; a launch fixture base configured to be connected to a supportstructure; and a docking device configured to secure the launch fixtureonto the launch fixture base, wherein the docking device comprises alaunch fixture slot passing through the docking device, wherein thelaunch fixture slot is configured to alternatively receive and securethe docking interface of the launch fixture through a top side of thedocking device and an opposing bottom side of the docking device.
 2. Thesystem as recited in claim 1, wherein the launch fixture includes: afirst fixation device configured to receive and secure the opticalfiber; a fiber storage area configured to receive and maintain theoptical fiber within specified dimensions; and a second fixation deviceconfigured to receive and secure the flexible OSS enabled instrument. 3.The system as recited in claim 2, wherein the launch fixture includes: alaunch region configured to receive and maintain the optical fiber in aknown geometric configuration before entering the second fixationdevice; and a defined path enabling correction for rotation of thelaunch region.
 4. The system as recited in claim 1, wherein the dockingdevice includes a plurality of connectors arranged to detachably fix thedocking device to the launch fixture base.
 5. The system as recited inclaim 4, wherein a geometry and a location of the plurality ofconnectors are symmetrically arranged on one of the top side or theopposing bottom side of the docking device.
 6. The system as recited inclaim 1, wherein the launch fixture includes a radio frequencyidentification associated with a type of the flexible OSS enabledinstrument.
 7. The system as recited in claim 6, further comprising: acontroller configured to recognize the radio frequency identification ofthe flexible OSS enabled instrument.
 8. The system as recited in claim1, further comprising: a display configured to display a virtualrepresentation of the flexible OSS enable instrument based on anidentification included on the launch fixture associated with thevirtual representation.
 9. The system as recited in claim 1, furthercomprising: a sterile drape arranged between the docking device and thelaunch fixture base when the docking device is securing the launchfixture onto the launch fixture base.
 10. The system as recited in claim1, wherein the launch fixture slot is slanted at an angle relative to amain axis of the support structure that reduces mechanical constraintson the optical fiber.
 11. An optical shape sensing (OSS) system,comprising: a plurality of launch fixtures configured to receive andsecure optical fibers within a plurality of flexible OSS enabledinstruments, respectively, wherein the plurality of launch fixturescomprise a plurality of docking interfaces, respectively; a launchfixture base configured to be connected to a support structure; and adocking device configured to secure the plurality of launch fixturesonto the launch fixture base, wherein the docking device comprises aplurality of slots passing through the docking device, wherein theplurality of slots are configured to receive and secure the plurality ofdocking interfaces of the plurality of launch fixtures, respectively,through a top side of the docking device and an opposing bottom side ofthe docking device.
 12. The system as recited in claim 11, wherein theplurality of slots are symmetrically arranged on each of the top sideand the opposing bottom side of the docking device.
 13. The system asrecited in claim 11, wherein the plurality of slots are slanted at anangle relative to a main axis of the support structure, reducingmechanical constraints on the optical fibers.
 14. The system as recitedin claim 11, wherein the plurality of launch fixtures includeidentifications associated with types of the flexible OSS enabledinstruments, respectively.
 15. The system as recited in claim 14,wherein the identifications are radio frequency identifications.
 16. Thesystem as recited in claim 11, wherein the plurality of launch fixturesinclude identifications associated with virtual representations of theflexible OSS enable instruments, respectively, wherein the systemfurther comprises: a display configured to display the virtualrepresentations of the flexible OSS enable instruments based on theidentifications.
 17. The system as recited in claim 11, furthercomprising: a sterile drape arranged between the docking device and thelaunch fixture base when the docking device is securing the plurality oflaunch fixtures onto the launch fixture base.
 18. An optical shapesensing (OSS) system, comprising: a launch fixture configured to receiveand secure an optical fiber within a flexible OSS enabled instrument,wherein the launch fixture comprises a docking interface; a launchfixture base attachable to a structure of a patient table at a pluralityof known locations, enabling registration of the launch fixture to apatient coordinate frame of reference and/or an imaging frame ofreference; and a docking device configured to secure the launch fixtureonto the launch fixture base, wherein the docking device comprises alaunch fixture slot passing through the docking device, wherein thelaunch fixture slot is configured to receive and secure the dockinginterface of the launch fixture through two sides of the docking device.19. The system of claim 18, wherein the launch fixture base maintains adefined geometric relationship with a frame of reference of thestructure such that re-registration of another launch fixture to thepatient coordinate frame of reference and/or the imaging frame ofreference is not required when another docking interface of the anotherlaunch fixture is received and secured in the launch fixture slot inplace exchange of the launch fixture.
 20. The system as recited in claim18, wherein the docking device includes at least one connector having ageometry and a location symmetrical with respect to a transversal planeof the docking device, wherein the transversal plane is perpendicular tothe patient table, such that the docking device is fixable to the launchfixture base after rotation about an axis perpendicular to a main axisof the patient table.